| Title | Magnetotelluric (MT) and Gravity Measurements in the Northern Negros Geothermal Field, Mt. Banlaon, Central Philippines |
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| Authors | David M. Rigor. Jr., Domingo B. Layugan and Carlos F. Los Banos |
| Year | 1997 |
| Conference | PNOC-EDC Geothermal Conference |
| Keywords | |
| Abstract | The observed broad positive gravity anomaly located at the center of the survey area is believed to be associated with the Canlaon Volcanic Complex. This anomaly is modeled to be a single diorite body at depth below 6 km that branched into three smaller bodies as it moved nearer the surface intruding the sedimentary deposits of the Basak, Talave and Caliling Formations. In between the two of the three modeled smaller bodies lies the Northern Negros geothermal system delineated by the -10 ohm-m resistivity anomaly defined by the magnetotelluric (AMT) survey. The - 10 ohm-m isoresistivity, contour at a depth of 2500, appear to be commonly bounded to the north by the 12 mgal gravity and the 50 to 130 ohm-m isoresistivity contours. The steep gravity, gradient near the positive ground peak possibly define a northwest trending structure that n1a.vserve as the southern boundary of the hydrothermal system. Among the recently drilled wells, PT-2D appears to be closest to the upflow region. KG-ID and CT-ID .that show relatively poorer permeability's are probably drilled at the edge of he reservoir nearer the interpreted high density intrusive body. PT-3D designed to penetrate the low resistivity anomaly defined by MT data is targeting the postulated center of resource. MT and gravity data suggest that the resource is hosted by the Caliling/Talave Sedimentary Formation. |